The PDB (Power Distribution board) is where both power enters from the battrey , and also provides a number of connector "translations" to match the motor and LED lighting. Specialized connectors on the motor and encoder to translate to the Dupont-style or standard DroneCode connector pinouts. It should be noted that the block diagram above does not show ALL the power distribution connections, which are as follows:
Battery input through a fuse
Battery voltage and current measurement through the INA226
3x Battery voltage outputs on 5 pin JST-GH for NavQPlus, MR-CANHUBK344, Extra
5V regulating supply for LED lights, and powering PWM servo rail on MR-CANHUBK344 and therefore the Servo itself.
PWM signals are consolidated into a single XHDP connector for ease of connection.
The GPS combines UART, I2C for Compass, and GPIO for switches, LED, and Beeper into a single large DroneCode standard connector.
The DCD-LZ interface simply combines SWD and a UART on a single JST-GH Dronecode connector. Depending on your kit you may have any of the following debug adapter boards:
FTDI USB-UART cable and adapter for UART/Console on the NavQPlus
FTDI USB-UART cable + DCD-LZ adapter for MR-CANHUBK344 DCD-LZ interface
In some systems you will find NeuralProbe board with USBC interface and connectors for UART/Console AND DCD-LZ interface. This board includes a USB-UART converter and also includes a button that will toggle the RST pin on SWD/JTAG interface. There is a 3rd interface on this board for Pixhawk V6X debug+uart connectors (not used here, used with NXP MR-VMU-RT1176)